ReiKey was designed to detect such keyboard taps, alerting you anytime a new tap is installed. In other words its goal is generically detect (the most common type of) macOS keyloggers.

Sometimes this does provide a false positive because certain apps with accessibility features or that respond to various keyboard commands will also use CoreGraphics event taps to respond to user input. Siri is a prime example.

But if you are interested in an app that can detect keyloggers on your Mac then give this a try.